Posted by Stuart on February 01, 2006 at 16:27:34:
Hi,
I often face a problem while calculating of some helical ratios. Specifications one of them are as under
Pinion Teeth = 22
Gear Teeth = 65
Normal Module = 7
Pressure Angle = 20°
Helix Angle = 14°.
Gear OD = 488mm,
Pinion OD = 178mm,
Centre Distance = 320mm.
I have a sample set of this ratio as well in my shop. All above dimensions are measured.
These dimensions do not match from that of my calculation. The outside diameter of pinion & gear is 172.714mm & 482.929mm respectively.
With reference to Centre Distance as 320mm , 7.139 module is the best one. But this module increase the gear OD and decrease the pinion OD .
It seems that helical gear can not be calculated with reference to their diameters like bevel gears. If it is so then which thing should I use as reference for calculation?
Is there any method to calculate helix angle & module with reference of centre distance?
Please reply
Thank you very much.
Stuart